1. Field of the Invention
This invention relates to an intravenous catheter introducing device, more particularly to an intravenous catheter introducing device with a needle cannula which is retractable into a barrel for safe disposal.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a self-retracting IV catheter introducer disclosed in U.S. Pat. No. 5,989,220 is shown to include a catheter connector assembly including a barrel 10 enclosing a retraction body 11 which has a front portion 111 that carries a needle cannula 12 and that extends through an opening in front of the barrel 10, and a rear portion 112 that is mounted within the barrel 10. The front portion 111 has a connection surface 111a which is frictionally engaged with a corresponding connection surface 131 of a catheter hub 13 so as to prevent rearward retraction of the retraction body 11. A biasing spring 15 is compressed against a ledge 101 at the front of the barrel 10, and a spring seat 113 of the retraction body 11. In use, the needle cannula 12 which extends through a flexible catheter 14 is inserted into a patient's vein to introduce the catheter 14 into the vein for intravenous delivery of fluid. The catheter hub 13 is then separated from the retraction body 11 by forcibly pulling the barrel 10 while holding the catheter hub 13 so that the catheter hub 13 is separated from the front portion 111 of the retraction body 11 by loosening of the connection surface 111a, and the retraction body 11 is immediately and automatically forced into the barrel 10 by the biasing spring 15, thereby drawing the used needle cannula 12 behind it. However, since the needle cannula 12 is drawn as soon as the catheter hub 13 is disengaged from the retraction body 11, the drawing operation is not manually controllable, which may lead to an undesirable withdrawal of the needle cannula 12 that may result in an accident, such as dropping of the barrel 10.